sodininkystė ir daržininkystė 25(4)

Rootstock field trials were established in three-four replications with 4 trees in
each experimental plot. Tree planting distances were 5 x 2.5–3 m. Orchard floor
management combined herbicide strips in the rows and frequent mown sward between
the rows. In the first experiments tree canopies were trained close to the
natural, in recent ones – as spindles.
Tree growth vigour in the first year of growth was assessed by total shoot
length or tree height, latter – by trunk diameter. Yield was recorded for the whole
experimental plot and recalculated to the yield per tree or per hectare. Annual yield
efficiency was calculated as a ratio of tree yield with trunk cross-section area (TCSA).
Final yield efficiency is a sum of annual efficiencies. Average fruit weight was determined
on a representative sample of 100 fruits per each experimental plot. Rootstock
suckering was evaluated in scores (0–5 scale, where 0 – no suckers; 5 –
abundant suckering) or number of suckers per tree was calculated. Tree mortality
was expressed as a percent of dead trees at the end of experiment.
For data statistical evaluation LSD 05
or Duncan test was used.
Results. Cherry rootstocks. Seedlings derived from accidental P. mahaleb, P.
avium or P. cerasus seeds were used as rootstocks for sour and sweet cherries.
After the experiments carried out by A. ðumskis in 1984–1998 seedlings of sweet
cherry cv. ‘Zolotaja Losickaja’, selection form No. 2 and two forms of P. mahaleb
(No. 817 and No. 805) were recommended as rootstocks for sour cherries (Ðumskis,
2001). Cherry trees on seedlings of mentioned forms ensured more uniform tree
growth and higher yields of good quality fruits. Tree survival on these rootstocks
was better. They withstand well cold winter of 1986–1987 and other unfavorable
conditions during the years of the experiment.
Parallel search of clonal rootstocks was started in the nursery. There were
selected some winter hardy, disease resistant and easy propagating by green cuttings
clonal rootstocks: PN (P. cerasus), P3, P7 (both P. padus x (P. cerasus x P. avium)
all bread at the Nonchernoziom Institute of Horticulture in Russia (Åâñòðàòîâ, 1986)
and Þ1 (P. cerasus) selected at the LIH (Ðumskis, 1997). Their testing in the orchard
was started in 1999. Mentioned rootstocks were tested with both sour and sweet
cherries. P. mahaleb seedlings served as a control.
The most vigorous sour cherry trees in the young age were on rootstock P7
(Table 1). With the rest of rootstocks tree growth was similar. Yield per tree, yield
efficiency and average fruit weight was not significantly affected by the rootstock
(Lanauskas, 2005 a). The most suckering rootstocks were P3 and P7. The highest
tree mortality was on rootstocks P7 and PN. None of tested rootstocks showed
better than standard one – P. mahaleb seedlings.
The least growth of sweet cherries was on rootstocks Þ1 and P7 (Table 2).
Tree mortality on these rootstocks was the highest (Lanauskas, 2005 b). The most
vigorous trees were on rootstock PN, but their trunk diameter was close to the one
of trees on P3 and P. mahaleb seedlings. The highest yield and yield efficiency was
of trees on rootstock P3, but this rootstock suckered profusely. The lowest yield
and yield efficiency was recorded for trees on P. mahaleb seedlings.
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